Each year I make terrariums with 120 second graders at my elem. school. It's a lot of fun, and the kids love doing it, but every year I stress over getting appropriate plants. Because of the expense, I cannot afford individual tropical plants; I just buy flats of plants from the nursery, but I have yet to find anything that really likes the humidity of a terrarium.
I have tried needlepoint ivy and various mosses, violets. The one that does the best is the ivy, but not always.
Any ideas for inexpensive plants I could use?